Brothers in Arms: Retribution Series by Carol Ericson

An experiment gone wrong unleashes the most elite killers on the planet When an unstable patient opens fire on Ava Whitman's lab, only a bulletproof window and agent Max Duvall stand between her and certain death. Max vows to prevent Tempest--the covert ops agency behind the shooting--from killing the one witness left standing: Ava. But a victim of a brainwashing attempt, Max is battling his own demons... moreAn experiment gone wrong unleashes the most elite killers on the planet When an unstable patient opens fire on Ava Whitman's lab, only a bulletproof window and agent Max Duvall stand between her and certain death. Max vows to prevent Tempest--the covert ops agency behind the shooting--from killing the one witness left standing: Ava. But a victim of a brainwashing attempt, Max is battling his own demons. How can a man who has been programmed to become a mindless, soulless killer keep the emerald-eyed beauty safe? Now on the run and running out of time, Max has to use every ounce of strength to ignore his deadly tendencies. And every bit of willpower to not give in to his desire for Ava. less

An undercover agent has one assignment: protect a pregnant woman who may know a lot more than she's telling…   Nina Moore has no idea her life and the life of her unborn child are in danger. She only knows she's grateful for the handsome handyman helping her restore her bed-and-breakfast. But Jase Bennett isn't the average jack-of-all-trades—he's a special ops agent assigned to protect Nina from Tempest, the organization responsible for Nina's ex-fiancé's death... moreAn undercover agent has one assignment: protect a pregnant woman who may know a lot more than she's telling…   Nina Moore has no idea her life and the life of her unborn child are in danger. She only knows she's grateful for the handsome handyman helping her restore her bed-and-breakfast. But Jase Bennett isn't the average jack-of-all-trades—he's a special ops agent assigned to protect Nina from Tempest, the organization responsible for Nina's ex-fiancé's death. Getting close to the vulnerable beauty is easier than Jase expected…too easy. And when "fake fiancé" is added to his job description, the jaded agent is in over his head. But with the body count rising, Jase must risk it all to save Nina and her baby from Tempest's twisted plans… less

Christmas was supposed to be about joy and hope…not about thwarting terrorist plots Most covert agents weren't blessed with long careers. Mike Becker wasn't like most agents. On the cusp of early retirement, he's given one final assignment: babysit a single mother with a reputation for coming up with conspiracy theories. Except the bullets flying Claire Chadwick's way can't be dismissed. Now Mike will do anything to protect her and her son, and uncover the truth... moreChristmas was supposed to be about joy and hope…not about thwarting terrorist plots Most covert agents weren't blessed with long careers. Mike Becker wasn't like most agents. On the cusp of early retirement, he's given one final assignment: babysit a single mother with a reputation for coming up with conspiracy theories. Except the bullets flying Claire Chadwick's way can't be dismissed. Now Mike will do anything to protect her and her son, and uncover the truth. A truth that places them at the center of a terrorist attack on Christmas Day. Mike's career may be coming to a blazing finish, but in this woman he finally has a shot at the redemption that's eluded him for so long. less